Water-Soluble Or Water-Swellable Polymers As Water Loss Reducers In Cement Slurries

Abstract

This invention relates to water-soluble or water-swellable polymers, containing a) 25-35 mol. % of one or more recurrent structural units of formula (1), where R 1 and R 2 represent hydrogen, methyl or ethyl, A represents a linear or branched C 1 -C 12 -alkylene, and Q + stands for H + , NH 4 + , Li + , Na + , K + , ½Ca ++ , ½Mg ++ , ½Zn ++ , ⅓Al +++ , or organic ammonium ions of the formula [HNR 5 R 6 R 7 ] + , b) 3 to 8 mol. % of one or more recurrent structural units of formula (2), where R 1 represents hydrogen, methyl, or ethyl, X + stands for H + , NH 4 + , Li + , Na + , K + , ½Ca ++ , ½Mg ++ , ½Zn ++ , ⅓Al +++ , or organic ammonium ions of the formula [HNR 5 R 6 R 7 ] + , B is a linear or branched alkylene group with 1 to 6 carbon atoms, and n is a whole number between 0 and 5, and c) 57 to 72 mol. % of a (meth)acrylamide.

1 . A water-soluble or water-swellable polymer having a k value of 100 to 300, measured in 0.5% by weight solution in distilled water, containing
 a) 25-35 mol % of at least one recurrent structural unit of the formula (1)   
       
         
           
           
               
               
           
         
         
           in which 
           R 1 , R 2  are hydrogen, methyl or ethyl, 
           A is linear or branched C 1 -C 12 -alkylene, and 
           Q +  is H + , NH 4   + , Li + , Na + , K + , ½Ca ++ , ½Mg ++ , ½Zn ++ , ⅓Al +++ , organic ammonium ions of the formula [HNR 5 R 6 R 7 ] +  where R 5 , R 6  and R 7  may each independently be hydrogen, a linear or branched alkyl group having 1 to 22 carbon atoms, a linear or branched, mono- or polyunsaturated alkenyl group having 2 to 22 carbon atoms, a C 6 -C 22 -alkylamidopropyl group, a linear monohydroxyalkyl group having 2 to 10 carbon atoms or a linear or branched dihydroxyalkyl group having 3 to 10 carbon atoms, and where at least one of the R 5 , R 6  and R 7  radicals is not hydrogen, or mixtures of these ions, 
         
         b) 3 to 8 mol % of at least one recurrent structural unit of the formula (2) 
       
       
         
           
           
               
               
           
         
         
           in which 
           R 1  is hydrogen, methyl or ethyl, 
           X +  is H + , NH 4   + , Li + , Na + , K + , ½Ca ++ , ½Mg ++ , ½Zn ++ , ⅓Al +++ , organic ammonium ions of the formula [HNR 5 R 6 R 7 ] +  where R 5 , R 6  and R 7  may each independently be hydrogen, a linear or branched alkyl group having 1 to 22 carbon atoms, a linear or branched, mono- or polyunsaturated alkenyl group having 2 to 22 carbon atoms, a C 6 -C 22 -alkylamidopropyl group, a linear monohydroxyalkyl group having 2 to 10 carbon atoms or a linear or branched dihydroxyalkyl group having 3 to 10 carbon atoms, and where at least one of the R 5 , R 6  and R 7  radicals is not hydrogen, or mixtures of these ions, 
           B is a chemical bond, or a linear or branched alkylene group having 1 to 6 carbon atoms, and 
           n is an integer from 0 to 5, 
         
       
       and
 c) 57 to 72 mol % of at least one recurrent structural unit of the formula (3) 
 
       
         
           
           
               
               
           
         
         
           in which 
           R 1  is hydrogen, methyl or ethyl, and 
           R 3  and R 4  are each independently hydrogen, methyl, ethyl, n-propyl, isopropyl or butyl. 
         
       
     
     
         2 . The polymer as claimed in  claim 1 , wherein the at least one structural unit of the formula (1) is derived from monomers selected from the group consisting of acryloyldimethyltaurate, acryloyl-1,1-dimethyl-2-methyltaurate, acryloyltaurate, and acryloyl-N-methyltaurate. 
     
     
         3 . The polymer as claimed in  claim 1 , wherein the at least one structural unit of the formula (2) is derived from methacrylic acid, acrylic acid, carboxyethyl acrylate or higher oligomers of the formula (2) in which n is an integer of 2 or more. 
     
     
         4 . The polymer as claimed in  claim 1 , wherein the at least one structural unit of the formula (3) is derived from monomers selected from the group consisting of acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-diethylmethacrylamide, N,N-diethylacrylamide, N,N-dimethylmethacrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, N-tert-butylacrylamide and N-butylacrylamide. 
     
     
         5 . The polymer as claimed in  claim 1 , wherein Q +  in formula (1) is selected from the group consisting of NH 4   + , Na +  and mixtures of these ions and X +  in formula (2) is selected from the group consisting of H + , NH 4   + , Na +  and mixtures of these ions. 
     
     
         6 . The polymer as claimed in  claim 1 , containing 27.5 to 32.5 mol % of the structural units (1), 4.5 to 7.5 of the structural units (2) and 60 to 68 mol % of the structural units (3). 
     
     
         7 . The polymer as claimed in  claim 1 , in which the neutralization level of the structural units of the formula (1) is 95 to 100 mol %. 
     
     
         8 . The polymer as claimed in  claim 1 , in which n=0 in at least 70% of all the structural units of the formula (2). 
     
     
         9 . The polymer as claimed in  claim 1 , in which n is 0 or 1. 
     
     
         10 . The polymer as claimed in  claim 1 , in which formula (3) is derived from acrylamide. 
     
     
         11 . The polymer as claimed in  claim 1 , which contains structural units of
 a) 27.5 to 32.5 mol % of acryloyldimethyltaurate,   b) 4.5 to 7.5 mol % of acrylic acid, and   c) 60 to 68 mol % of acrylamide.   
     
     
         12 . The polymer as claimed in  claim 1 , in which formula (1) represents acryloyldimethyltaurate, formula (2) represents acrylic acid and formula (3) represents acrylamide. 
     
     
         13 . A process for preparing a polymer comprising the steps of polymerizing
 a) 25-35 mol % of at least one recurrent structural unit of the formula (1)   
       
         
           
           
               
               
           
         
         
           in which 
           R 1 , R 2  are hydrogen, methyl or ethyl, 
           A is linear or branched C 1 -C 12 -alkylene, and 
           Q +  is H + , NH 4   + , Li + , Na + , K + , ½Ca ++ , ½Mg ++ , % Zn ++ , ⅓Al +++ , organic ammonium ions of the formula [HNR 5 R 6 R 7 ] +  where R 5 , R 6  and R 7  may each independently be hydrogen, a linear or branched alkyl group having 1 to 22 carbon atoms, a linear or branched, mono- or polyunsaturated alkenyl group having 2 to 22 carbon atoms, a C 6 -C 22 -alkylamidopropyl group, a linear monohydroxyalkyl group having 2 to 10 carbon atoms or a linear or branched dihydroxyalkyl group having 3 to 10 carbon atoms, and where at least one of the R 5 , R 6  and R 7  radicals is not hydrogen, or mixtures of these ions, 
         
         b) 3 to 8 mol % of at least one recurrent structural unit of the formula (2) 
       
       
         
           
           
               
               
           
         
         
           in which 
           R 1  is hydrogen, methyl or ethyl, 
           X +  is H + , NH 4   + , Li + , Na + , K + , ½Ca ++ , ½Mg ++ , ½Zn ++ , ⅓Al +++ , organic ammonium ions of the formula [HNR 5 R 6 R 7 ] +  where R 5 , R 6  and R 7  may each independently be hydrogen, a linear or branched alkyl group having 1 to 22 carbon atoms, a linear or branched, mono- or polyunsaturated alkenyl group having 2 to 22 carbon atoms, a C 6 -C 22 -alkylamidopropyl group, a linear monohydroxyalkyl group having 2 to 10 carbon atoms or a linear or branched dihydroxyalkyl group having 3 to 10 carbon atoms, and where at least one of the R 5 , R 6  and R 7  radicals is not hydrogen, or mixtures of these ions, 
           B is a chemical bond, or a linear or branched alkylene group having 1 to 6 carbon atoms, and 
           n is an integer from 0 to 5, 
         
       
       and
 c) 57 to 72 mol % of at least one recurrent structural unit of the formula (3) 
 
       
         
           
           
               
               
           
         
         
           in which 
           R 1  is hydrogen, methyl or ethyl, and 
           R 3  and R 4  are each independently hydrogen, methyl, ethyl, n-propyl, isopropyl or butyl via free-radical precipitation polymerization in a polar solvent, and the monomers are optionally neutralized prior to the polymerization, or the polymer is optionally neutralized after the polymerization, with ammonia, ammonium carbonate or organic amines or an Li + -, Na + -, K + -, Ca ++ -, Mg ++ -, Zn ++ - or Al +++ -containing base. 
         
       
     
     
         14 . The process as claimed in  claim 13 , wherein the polar solvent has a boiling point of 60 to 110° C. 
     
     
         15 . The process as claimed in  claim 13 , wherein the polar solvent is a solvent mixture of
 d) water   
       and
 e) at least one further polar solvent. 
 
     
     
         16 . The process as claimed in  claim 13 , wherein the polar solvent comprises methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, 1-butanol, 2-butanol, dimethyl ketone, diethyl ketone, pentan-2-one, butanone, tetrahydropyran, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxane or 1,4-dioxane. 
     
     
         17 . The process as claimed in  claim 13 , in which the polar solvent comprises 2-methylpropan-2-ol. 
     
     
         18 . The process as claimed in  claim 13 , wherein the polar solvent comprises 1% to 5% by weight of water. 
     
     
         19 . The process as claimed in  claim 13 , wherein 27.5 to 32.5 mol % of acryloyldimethyltaurate, and 4.5 to 7.5 mol % of acrylic acid, 60 to 68 mol % of acrylamide is subjected to free-radical precipitation polymerization a mixture of 1% to 8% by weight of water and 92% to 99% by weight of 2-methylpropan-2-ol, and the monomers prior to the polymerization or the polymer after the polymerization are/is optionally neutralized with ammonia, ammonium carbonate, sodium hydroxide, sodium carbonate. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . A method for cementing deep wells using a cement slurry, wherein the cement slurry comprises a polymer as claimed in  claim 1 . 
     
     
         23 . The method as claimed in  claim 22 , in which the polymer content is 0.05% to 5% by weight, based on the cement slurry. 
     
     
         24 . A polymer mixture containing 25% to 75% by weight of a polymer as claimed in  claim 1 , and 25% to 75% by weight of starch, chemically modified starch or thermally modified starch.